4 research outputs found
Co-appearance of superconductivity and ferromagnetism in a CaRuO nanofilm crystal
By tuning the physical and chemical pressures of layered perovskite materials
we can realize the quantum states of both superconductors and insulators. By
reducing the thickness of a layered crystal to a nanometer level, a nanofilm
crystal can provide novel quantum states that have not previously been found in
bulk crystals. Here we report the realization of high-temperature
superconductivity in CaRuO nanofilm single crystals. CaRuO thin
film with the highest transition temperature (midpoint) of 64~K exhibits
zero resistance in electric transport measurements. The superconducting
critical current exhibited a logarithmic dependence on temperature and was
enhanced by an external magnetic field. Magnetic measurements revealed a
ferromagnetic transition at 180~K and diamagnetic magnetization due to
superconductivity. Our results suggest the co-appearance of superconductivity
and ferromagnetism in CaRuO nanofilm crystals. We also found that the
induced bias current and the tuned film thickness caused a
superconductor-insulator transition. The fabrication of micro-nanocrystals made
of layered material enables us to discuss rich superconducting phenomena in
ruthenates